The invention concerns a yarn texturing nozzle having a compression section. A nozzle of this kind is described for example in the German patent application DE 20 36 856. The yarn entering from above into the nozzle is conveyed by a hot-air stream to a compression section which is provided with openings that are for example of slot shape. By lateral escape of the injected air, a compression of the endless fibre and thus also a deceleration occurs due to the rate of speed reduction within the passage channel. The thereby formed yarn plug is relatively slowly discharged from the nozzle and is thereby cooled down. A rotary cooling drum can be used, on whose surface the compressed yarn is laid and whereby through perforations in the drum air of lower temperature than in the nozzle prevails, e.g. room air, for the cooling of the yarn.
The invention relates to the compression section of a texturing nozzle, in particular to a BCF texturing nozzle, for high speeds. The compression section of a texturing nozzle is conventionally made up of an upper lamellar holder, an end piece and a number of lamellar. In a modified exemplified embodiment, the compression section can also be a tube type piece, which over a section of its length is being provided with a number of longitudinal slots.
The texturing air and the yarn enter the compression section from above at high speed, that is in the flow direction of the fibres or the air respectively. In the area of the compression section, the air flows more or less radially all of a sudden through the slots or the gaps respectively between the lamellar and to a large extent discharges outward to the outside of the lamellar. This causes a reduction of the air speed within the longitudinal channel of the nozzle. Thus the yarn is decelerated and forms a plug which fills the whole diameter of the slotted part, that is the compression section. The plug then slides further downwards through a plug guide tube and further on to a cooling drum or to a conveying device, in particular a pair of rollers. It cannot be prevented that at this position at which the air leaves the slot, single fibrils can be loosened from the yarn and be pulled more or less far outward radially into the slots. Loops can also leave the slots extending beyond the outer edges of the lamellar, thereby said loops can get mutually entangled with loops extending from the neighboring slots. Since the loops or fibres between the slots exiting laterally from the actual yarn or plug guide tube respectively, move downwards together with the plug, they hit the end piece, or in the case of another exemplified embodiment hit an edge or pocket respectively, forming the end of the slot. Thus single loops may remain hooked and thus be pulled far out from the plug or even get torn off. In practice, said protruding loops or filament parts in the finished yarn are known as xe2x80x9cpullersxe2x80x9d (Zupfers), which can cause difficulties during further processing.
The improved compression section consists of a tube type piece with slots in the longitudinal direction. According to the invention, these slots are completely open at their lower ends and the lamellar formed by these slots area only connected with each other at the upper end, or they are connected to each other at a distance from the lower end in circumferential direction and in opposite direction to the nozzle. In other words, the lamellar are fastened at the air or the yarn entering point respectively, or close to it at the compression section or the lamellar holder respectively. They can also be fastened to a flange, which again is screwed onto a conveying means at the inlet side of the texturing nozzle or which is fastened with other fastening means. In the outflow direction of the air or in conveying direction of the plug respectively, the lamellar are without contact to parts surrounding the nozzle, in particular without contact to an end piece or a guiding part for the plug succeeding the compression section. The plug guide tube following the compression section, i.e. the portion opposite the free ends of the lamellar, forms, together with the lower end of the compression section, a narrow gap, in particular a truncated cone shaped gap.
Since the ends of the lamellar are free in the downward direction and without contact to the surrounding parts of the nozzle, the filament loops exiting the slots or gaps respectively between the lamellar have no chance to entangle or to remain hooked, whereat the formation of pullers (Zupfer) or broken fibrils is suppressed or considerably reduced respectively. If the fibrils exiting between the lamellar hit the truncated cone-shaped inlet part of the guiding part or end piece respectively, then they come to lay on a smooth surface without niches and edges, and therefore, the risk of pulling-out from the plug does practically not exist anymore. Thus, with the suggested configuration of the compression section the running reliability of the texturing nozzle is considerably increased.
The compression section according to the invention can be used for all types of nozzles by which a yarn plug is formed, that is for instance also for the type of a plug formation through friction within the compression section, or with nozzles by which the plug formation is controlled by a cooling drum succeeding the texturing nozzle, or with nozzles, which are succeeded by a pair of rollers for controlling the plug formation.
As mentioned, it is an object of the invention to increase the operating reliability of a nozzle, in that a compact plug is being formed without fibrils projecting out from said plug. Additional object and advantages of the invention will be set forth.
The texturing device according to the invention is characterized by a nozzle with an inlet part, a conveying part, a compression section and a guiding part, whereat between the inlet part and the conveying part hot air or steam is let into a yarn guiding channel, which can exit within the zone of the compression section, whereat the lamellar at the outlet side of the compression section are free towards the surrounding, in particular without contact to the parts surrounding the nozzle and/or to a succeeding guiding part. In the conveying direction, a conveying part is arranged in front of the compression section and behind the compression section lays a guiding part or plug guide tube. On the inlet side of the compression section the lamellar are held by a lamellar holder, whereat the inlet side is neighboring a conveying part next to the nozzle inlet. The lamellar at the end opposing the inlet side of the nozzle freely project without support in the downward direction. The outer contour of the lamellar is either parallel to the conveying direction of the air or the textile fibres respectively, or is at a slant angle to it. In particular, at the outlet side the lamellar are slanted on their outside. Since the lamellar are arranged circularly, their outer contours around a conveying channel for a yarn plug, which lays inside the compression section, describe a contour in the form of a truncated cone-shaped shell surface. Accordingly, the succeeding guiding part or plug guide tube respectively, following the compression section is provided in the form of a truncated cone-shaped inlet funnel of the following guiding part, a gap, a ring shaped gap in particular, which preferably is of the shape of a truncated cone shall. The nozzle is to be applied as texturing nozzle for filament yarns. Following the nozzle a conveying means if arranged, for instance a pair of rollers or a drum, to convey the textured yarn or the plug respectively, the latter being furnished with a channel to guide the yarn plug.
Within a texturing device, in particular at a maximum length of the compression section of 60 mm, a guiding part at maximum of the same length follows, in which the texturized yarn in the form of a plug can be led to the surface of the drum, and then following this first guiding part, after a deviation, a second guiding part alongside the surface of the drum is provided, in that on one hand the texturized yarn is led in the radial and on the other hand in the axial direction of the drum.
The invention is being described in the following by way of the drawings.